Metal foil package for annealing



2 Sheets-Sheet 1 W. J. NEUHAUSER ETAL METAL FOIL PACKAGE FOR ANNEALING Original Filed Nov. 19, 1959 Nov. 10, 1964 Elma/whom- WILLIAM JOHN NEUHAUSER ROLAND VALENTINE VILLIERS 10, 1964 w. J. NEUHAUSER ETAL 3,156,357

METAL FOIL PACKAGE FOR ANNEALING Original Filed Nov. 19,1959

2 SheetsSheet 2 grwwwtom WILLIAM JOHN NEUHAUER ROLAND VALENTINE VILLIERS flmun #M/Qaa labels.

United States Patent METAL FGIL PACKAGE FOR ANNEALING William John Neuhauser and Roland Valentine Villiers,

Louisville, Ky., assignors to Reynolds Metals (10mpany, Richmond, Va, a corporation of Delaware Original application Nov. 19, 1959, Ser. No. 854,061, now Patent No. 3,067,073, dated Dec. 4, 1962. Divided and this application Feb. 20, 1962, Ser. No. 182,701

Claims. (Cl. 206-59) This application is a division of application Serial No. 854,061, filed November 19, 1959, now United States Patent No. 3,067,073 issued December 4, 1962.

This invention relates to the production of metal foil. More particularly, this invention relates to the treatment of rolled aluminum foil by annealing so as to improve the flexibility of the foil and remove rolling oil from the foil to improve the surface characteristics thereof as regards subsequent adhesion thereto of printing ink and The annealing of the roll of aluminum foil is carried out preparatory to subsequent operations such as slitting, laminating'to paper stock, printing, et cetera'.

In the production of aluminum foil, aluminum billets are rolled down to foil stock by passing the metal a number of times through hot rolling mills and then finally through one or more cold mills until a thickness of 0.5- 0.7 millimeter is reached. This foil stock, as it is called, is usually annealed before cold rolling further to foil gauges. In the cold rolling the metal is reduced to about half thickness with each pass through the cold mills. The final aluminum foil produced by the cold rolling is a thin sheet below about 0.15 millimeter in thickness.

A great deal of heat is generated during both the hot and cold rolling, and has to be taken away evenly so that hot spots do not develop to cause roll distortion and bellies in the foil.

To remove this heat, oil is sprayed on the rolls, not only cooling them but also lubricating the metal. The metal coming from the rolling mill is oily with the lubricant, and because of the work which is being done on it, is hard and springy. A limited quantity of foil is used in this hard condition because the hard foil is less liable to distortion and damage than is annealed foil.

The oil on the hard foil makes good adhesion of paper to foil diflicult, and the foil is generally too springy and relatively brittle. It is usual therefore, to anneal aluminum foil to give it relatively dead folding characteristics. Annealing consists of heating the foil in spool or roll form for a number of hours at temperatures not far short of dull red heat, namely about 650 degrees Fahrenheit to about 800 degrees Fahrenheit. The annealing process reduces brittleness and removes a major portion of the lubricating oil by vaporization. Also, the annealing process gives a completely sterile surface to the aluminum foil.

Heretofore, in annealing a cylindrical roll of aluminum foil wound on a core or stem, it has been found that during annealing, the amount of heat entering the ends of the roll of aluminum foil is approximately three times the amount of heat entering the roll through the curved cylindrical surface thereof. This non-uniform flow of heat produces undesirable effects in the foil. It has also been found that, after annealing according to prior procedures, the end surface areas of the rolled foil have residual oil stain therein which makes the foil unacceptable for many uses. The oil stain on the edges of the foil makes the foil unsightly. Further, the oil stain interferes with proper printing of the foil.

In accordance with the present invention, these ditficulties are overcome by wrapping the roll of aluminum foil in a package which provides for substantially uniform heat flow through the roll and eliminates the oil stain on the edge surfaces of the foil.

For a better understanding of the invention and its 3,155,357 Patented Nov. 10, 1964 '2 other objects, advantages and details, reference is now made to the present preferred embodiment of the invention which is shown, for purposes of illustration only, in the accompanying drawings.

In the drawings:

FIG. 1 is a vertical section illustrating the initial step in forming a package according to the invention wherein end sheets of aluminum foil are placed adjacent each end of a roll of metal foil wound upon a core;

FIG. 2 is a vertical section illustrating a subsequent step in forming a package according to the invention wherein asbestos discs are placed at each end of the roll adjacent the end sheets of aluminum foil;

FIG. 3 is an end elevation of the combination of elements illustrated in FIG. 2;

FIG. 4 is a vertical section illustrating a subsequent step in forming a package according to the invention wherein the edge portions of the aluminum foil and sheets are folded over the edges of the asbestos discs;

FIG. 5 is an end elevation of the combination of elements illustrated in FIG. 4;

FIG. 6 is an end elevation illustrating a subsequent step in forming a package according to the invention wherein four wrapping sheets of aluminum foil are placed adjacent the cylindrical periphery of the roll;

FIG. 7 is a vertical section illustrating a subsequent step in forming a package according to the invention wherein the four cover sheets of aluminum foil have been wrapped around the cylindrical periphery of the roll;

FIG. 8 is a vertical section illustrating the complete package wherein the ends of the four Wrapping sheets have been tucked in to engage the core and the package has been suspended in an annealing furnace; and,

FIG. 9 is a fragmentary vertical elevation of one end of the package illustrated in FIG. 8, shown on an enlarged scale, with the elements exploded, wherein the arrows indicate the paths of flow of the residual rolling oil vapors during annealing.

Referring to the drawings, the formation of a package of a roll of aluminum foil suitable for annealing is illustrated in FIGS. l to 8. In FIG. 1, a roll 20 of metal foil, such as aluminum foil, is illustrated wound upon a core having end-s 22 and 24 projecting from opposite ends of roll 20. The foil of roll 20 is springy and relatively brittle and is coated withoil applied during the previous rolling. A square end sheet of aluminum foil 26 is placed adjacent one end of roll 20 with the core end 22 extending through a central aperture in the end sheet 26. Similarly, a square end sheet of aluminum foil 28 is placed adjacent the other end of the roll 20 with the core end 24 extending through a central aperture in the sheet 26. The end sheets 26 and 28 have a thickness of about 00007 inch. Among the other thicknesses which can be employed are from about 0.00025 inch to about 0.0025 inch.

Next, referring to FIG. 2, a porous, heat-insulating, circular, asbestos disc 30 is placed adjacent the end foil sheet 26 with the core end 22 extending through a central aperture in the disc 30. Similarly, a porous, heatinsulating, circular, asbestos disc 32 is placed adjacent the end foil sheet 23 with the core end 24 extending through a central aperture in asbestos disc 32. As seen in FIG. 3, the square end sheets 26 and 28 have greater widths than the diameter of roll 20 and discs 3% and 32 so that the edge portions of the end sheets 26 and 23 extend outwardly beyond the discs. The discs 30 and 32 are formed of 32-pound asbestos.

Referring to FIGS. 4 and 5, the corners 34 of the foil end sheet 26 are folded over the disc 30 and pressed against the outer surface of disc 30. In like manner, the corners 36 of foil end sheet 28 are folded over the disc 32 and pressed against the outer surface of disc 32.

Thereafter, two superposed cover or wrapping sheets 40 and 42 are placed over the cylindrical periphery of roll 26} with their ends extending for a substantial distance beyond one end of roll 20. Another pair of superposed cover or wrapping Sheets 44 and 46 are placed over the periphery of roll with their inner ends overlapping the sheets 49 and 4 2 and their outer ends extending for a substantial distance beyond the other end of roll 20. The wrapping sheets 40, 42, 44 and 46 are formed of aluminum foil of 0.0012 inch thickness. It will be seen in FIG. 7 that in the center of roll 20, the wrapping is four sheets thick.

The extending ends of the wrapping sheets are then folded and tucked inwardly toward the core ends 22 and 24. Referring to FIG. 8, a tucked sealing rib 50 is formed by packing the ends of wrapping sheets and 42 around the core end 22. Similarly, a tucked sealing rib 52 is formed by packing the ends of wrapping sheets 44 and 46 around the core end 24. Thus, the aluminum foil package 60 is formed as shown in FIG. 8 and suspended in a dry annealing furnace 62.

For clarity of illustration, the scale of elements shown in the drawing is distorted. Some of the elements are shown to an enlarged scale of thickness.

The aluminum foil package 60 is dry annealed in furnace 62 at temperatures from about 650 degrees Fahrenheit to about 800 degrees Fahrenheit. The annealing reduces the brittleness of the foil in roll 20. Further, the annealing gives it dead folding characteristics, that is, reduces the springiness of the foil. The annealing also vaporizes the rolling oil from the roll 20 and produces foil free of end roll stain.

Each element of the package plays a part in achieving these advantageous results. Referring to FIG. 9, the arrows indicate the probable paths of flow of the oil vapors as they leave the roll 20. The asbestos discs 30 and 32 equalize the heat flow through the roll 20 during the annealing cycle. It has been determined experimentally that during annealing the amount of heat entering the ends of a roll of aluminum foil is approximately three times the amount of heat entering the roll through its cylindrical peripheral area. The insulating value of the asbestos discs 3%) and 32 effectively reduces this 3 to 1 heat flow ratio to a point where substantially uniform heat flow through the roll is obtained which is extremely desirable in aluminum foil dry annealing.

Further, the asbestos discs 30 and 32 absorb some of the residual rolling oil which has been driven from the roll 20 during the annealing cycle.

The end sheets 26 and 28 prevent staining of the ends of roll 29 by the residual rolling oil that is driven from the foil roll 2% during the annealing cycle. While the invention is not to be limited by theoretical explanations of its operation, the following are possible modes in which the end sheets 26 and 23 prevent end roll stain: 1) The major portion of rolling oil vapor is absorbed by the asbestos discs but a certain amount remains unabsorbed. This unabsorbed vapor condenses on the end sheets 26 and 28 instead of on the ends of roll 28. (2) The residual rolling oil absorbed by the asbestos discs is prevented from migrating to the ends of roll 20 by the end sheets 26 and 28 acting as barriers between the asbestos discs and the roll 20.

The wrapping sheets 46, 42, 44, and 46 secure the asbestos discs 30 and 32 and the end foil sheets 26 and 28 in position adjacent the ends of foil roll 28.

Thus it will be seen that the invention provides a metal foil roll packaged for uniform heating in an annealing furnace wherein the package elements produce substantially complete removal of residual rolling oil from the foil roll and also provide for uniform heating of the roll during annealing.

While a present preferred embodiment of the invention has been illustrated and described, it will be recognized that the invention can be otherwise variously embodied and practiced within the scope of the followin claims.

We claim:

1. A package suited for annealing comprising a roll of metal foil having a substantial cylindrical surface area and end areas of different heat-flow properties than said surface; an end sheet of gas-impermeable material adjacent each end of said roll; a plate of heat-insulating porous material adjacent each said end sheet on the side of said end sheet remote from said roll, the and sheets being folded over the edges of said plates and extending along the outer surfaces of said plates remote from the metal foil roll, said plates and sheets having together such heat insulating and deflecting qualities as to substantially equalize the flow of heat through the cylindrical surface and the end areas; and, a wrapper surrounding the roll and extending inwardly at the ends of the roll encasing the end sheets and plates whereby the entire surface of the metal foil, when exposed to annealing heat, can be annealed with substantial uniformity.

2. A package as set forth in claim 1 wherein said end sheets are metal foil and said heat-insulating orous plates are asbestos discs.

3. The invention as set forth in claim 2 wherein said wrapper includes a plurality of aluminum foil cover sheets overlapping at the center of said roll.

4. A package suited for annealing comprising a cylindrical roll of spirally-wound aluminum foil; a separate end sheet of gas-impermeable aluminum foil adjacent each end of said roll, said end sheet extending over substantially the entire area of the roll end; an asbestos disc adjacent each said aluminum end sheet on the side of said end sheet remote from said roll, said end sheets being folded over the edges of said adjacent discs and extending along the outer surfaces of said discs; and, a covering layer of aluminum foil including at least one wrapping sheet of foil and surrounding the cylindrical surface of said roll and extending inwardly at the ends of said roll to encase said end sheets and said discs; said asbestos discs and said foil sheets having such insulation and heat deflecting properties and dimensions as to substantially equalize the flow of annealing heat to all parts of said spirally wound foil.

5. A package suited for annealing comprising. a cylindrical roll of aluminum foil Wound upon a core, the ends of said core projecting from opposite ends of said roll; a separate end sheet of aluminum foil adjacent each end of said roll, said end sheet extending over substantially the entire area of the roll end; an asbestos disc adjacent each said end sheet on the side of said end sheet remote from said roll, said core ends extending through registering apertures in said asbestos discs and said end sheets; the edges of said end sheets being folded over the edges of respective adjacent asbestos discs and extending along the outer surfaces of said discs; and, a wrapper of aluminum foil surrounding the roll and extending inwardly at the ends of the roll and packed around the circumference of said core ends to encase said end sheets and said asbestos discs; the asbestos discs and end sheets having together such insulating and heat deflecting properties as to substantially equalize the flow of annealing heat to all parts of said wound foil, which flow would be unequal in their absence.

References Cited in the file of this patent UNITED STATES PATENTS 2,212,668 Mirfield Aug. 27, 1940 2,460,434 Salem Feb. 1, 1949 2,538,244 Hileman Jan. 16, 1951 2,555,205 Steifens May 29, 1951 2,573,816 Thompson Nov. 6, 1951 2,647,816 Battist Aug. 4, 1953 2,869,719 Hubbard Jan. 20, 1959 2.883.045 Abramson Apr. 21, 1959 

5. A PACKAGE SUITED FOR ANNEALING COMPRISING, A CYLINDRICAL ROLL OF ALUMINUM FOIL WOUND UPON A CORE, THE ENDS OF SAID CORE PROJECTING FROM OPPOSITE ENDS OF SAID ROLL; A SEPARATE END SHEET OF ALUMINUM FOIL ADJACENT EACH END OF SAID ROLL, SAID END SHEET EXTENDING OVER SUBSTANTIALLY THE ENTIRE AREA OF THE ROLL END; AN ASBESTOS DISC ADJACENT EACH SAID END SHEET ON THE SIDE OF SAID END SHEET REMOTE FROM SAID ROLL, SAID CORE ENDS EXTENDING THROUGH REGISTERING APERTURES IN SAID ASBESTOS DISCS AND SAID END SHEETS; THE EDGES OF SAID END SHEETS BEING FOLDED OVER THE EDGES OF RESPECTIVE ADJACENT ASBESTOS DISCS AND EXTENDING ALONG THE OUTER SURFACES OF SAID DISCS; AND, A WRAPPER OF ALUMINUM FOIL SURROUNDING THE ROLL AND EXTENDING INWARDLY AT THE ENDS OF THE ROLL AND PACKED AROUND THE CIRCUMFERENCE OF SAID CORE ENDS TO ENCASE SAID END SHEETS AND SAID ASBESTOS DISCS; THE ASBESTOS DISCS AND END SHEETS HAVING 